1. Field of the Invention
The present invention relates to a portable, combustion-engined setting tool for fastening elements and including a base body, a guide tube for fastening elements, a piston rod for driving fastening elements out of the guide tube, and a locking device for lockingly connecting the guide tube with the base body.
2. Description of the Prior Art
Setting tools of a type described above are generally known and can be formed, e.g., as explosive powder charge-actuated, bolt setting tool. With such setting tools, in accordance with the performed operation, i.e., in accordance with the accessibility of the treated location or the type of the set fastening elements, and for maintenance work, the guide tube should be capable of being quickly dismounted or mounted. When the mounting is effected by using a threaded connection, the guide tube should be capable of being stopped at a predetermined point to insure permanently a uniform piston stroke and thereby a uniform penetration depth of the fastening element.
Up to the present, a spring-biased, extending in the setting or longitudinal direction of the guide tube, pin, which was chamfered at one end, has been used. The pin, upon the guide tube reaching a predetermined screw-in depth during screwing of the guide tube into the tool base body, becomes engaged in a groove formed in the base body, preventing further screwing-in of the guide tube. For screwing the guide tube out of the base body, a torque dependent on the inclination angle of the pin and the applied biasing force, should have been overcome in order to withdraw the pin over its chamfer out of the groove to enable unscrewing of the guide tube.
The problem with such a pin, consists in that an unintentional unscrewing of the guide tube, as a result of rotation of the setting tool with the fixed guide tube, can take place, in particular during operation in a narrow space. This can lead to an inevitable damage of the setting tool. In addition, decrease of the biasing force, e.g., as result of fatigue or increase in contamination, directly influences the unscrewing torque, which further increase the danger of the setting tool being damaged.
Accordingly, an object of the present invention is a setting tool of a type described above which would insure a reliable operational process.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing, in a setting tool of the type described above, a locking device including a locking nose carried by the guide tube, a spring for radially biasing the locking nose away from the guide tube with the locking nose being manually radially displaceable toward the guide tube against a biasing force of a spring into a groove provided in the base body.
Thus, according to the invention, there is provided, in a setting tool, a spring-biased, locking nose extending in a direction transverse to the setting direction and which, upon the guide tube reaching a predetermined screw-in depth during screwing of the guide tube into the tool base body, becomes engaged in a radial groove provided in the base body, preventing both further screwing-in and unscrewing of the guide tube. When the guide tube needs to be removed, the locking nose should be manually disengaged from the groove by a tool user. An automatic unscrewing of the guide tube from the base body is not any more possible. Thereby, a reliable operational process is insured and, in addition, there is provided a possibility to quickly and simply connect the guide tube with the base body or disconnect the guide tube from the base body.
According to one embodiment of the present invention, the locking nose has a locking rim extending toward a longitudinal axis of the guide tube under an acute angle that opens toward a mouth opening of the guide tube. Thereby, the locking nose can be easily pushed, in a simple way, in the direction toward the base body and, finally, be rotated into the groove, upon the guide tube being rotated to screw the guide tube into the base body. The locking nose is, to some extent, being screwed into the groove, or it can engage in the groove in a bayonet-like manner. The locking nose can already engage in an opening provided for effecting screwing of the guide tube into the tool base body before, finally, engaging in the groove upon further rotation.
According to a further embodiment of the present invention the locking nose forms part of a locking member having a pin element extending radially toward the guide tube and supporting the compression spring supported in a radial recess formed in the guide tube.
In this way, a precise positioning and displacement of the locking nose is insured. Furthermore, the radial arrangement of the compression spring reduces the load applied to the spring during the setting process which, in turn, reduces the spring fatigue and, thereby, the danger of a fatigue fracture.
Advantageously, there is provided an adjusting member formed integrally with the locking member. The adjusting member provides for displacement of the locking member and, thereby, the locking nose against the biasing force of the compression spring. The adjusting member provides for a manual displacement of the locking nose by the tool user. The user can act on the adjusting member either directly or indirectly, with an axially displaceable adjusting sleeve that is slidably supported on the guide tube. The adjusting sleeve is displaced in the longitudinal direction of the guide sleeve in a direction away from the mouth opening of the guide tube. Thereby, a possible laborious inquiry of the position of the adjusting member by the user is avoided. Besides, grasping of the adjusting sleeve is much easier than pressing the adjusting member.
According to an advantageous embodiment of the present invention, the adjusting member has an adjusting rim extending toward a longitudinal axis of the guide tube at an acute angle that opens in a direction away from the mouth opening of the guide tube. When the adjusting sleeve is pushed away from the mouth opening of the guide tube, the sleeve can easily run on the adjusting edge of the adjusting member, displacing the locking nose, by the adjusting member, in the radial direction with respect to the guide tube. In this way, the process of removing the guide tube is further simplified. Preferably, the adjusting sleeve is displaced in the direction away from the mouth opening of the guide tube against a spring-biasing force applied by a further compression spring. This facilitate displacement of the adjusting sleeve to its initial position.
According to a further development of the present invention, there is provided, in the tool base body, guide tube-side means for guiding the locking nose and for limiting radial displacement of the locking nose in a direction away from the guide tube. To this end, the locking nose or the locking member, with which the locking nose is formed as one piece, is slidably displaceably arranged in a slot that lies in the same plane as the central axis of the guide tube. Preferably the locking nose, locking member, and the adjusting member are formed as a one-piece flat-shaped element. In this case, slot and plate planes overlap each other. For limiting the displacement of the adjusting member in a radial direction away from the guide tube, a limiting ring can be provided on the guide tube against which the adjusting member is biased by the compression spring located in a radial recess formed in the guide tube. Instead of a limiting ring, however, another suitable stop can be used for limiting the displacement of the adjusting member in the radial direction away from the guide tube.
The guide tube can be so formed that the fastening elements are pushed into the guide tube from the tube month opening. In this case, the guide tube is completely circumferentially closed over the entire displacement path of a fastening element.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.